Answer:— When the air inside the balloon is heated, it expands and becomes less dense than the cooler air outside, causing the balloon to rise.Additional Knowledge:Charles's Law Principle:At constant pressure, the volume of a gas increases as its temperature increases.Application in Hot Air Balloons:Heating the air inside the balloon increases its volumeExpanded warm air becomes lighter than the surrounding airThis difference in density allows the balloon to float or riseConclusion:Charles’s Law explains why hot air balloons lift — warmer air takes up more space and rises above cooler air.